Chronically Low BMI in Children Increases Risk of Eating Disorders Later

Scientists may have identified a risk factor for eating disorders. After assessing data from 1,502 people that were part of the Avon Longitudinal Study of Parents and Children in the UK, it was found that as early as age two for boys and age four for girls, chronically low body mass index (BMI) may increase the risk of developing anorexia nervosa. Kids with persistently high BMI had an increased risk of developing other eating disorders - bulimia nervosa, purging disorder, and binge-eating disorder. The work has been reported in the Journal of the American Academy of Child and Adolescent Psychiatry, and supports the idea that there are physiological and genetic factors that influence the development of eating disorders.

"Until now, we have had very little guidance on how to identify children who might be at increased risk for developing eating disorders later in adolescence," said the first author of the report Zeynep Yilmaz, Ph.D., an assistant professor of psychiatry and genetics with the UNC Center of Excellence for Eating Disorders at the UNC School of Medicine. "By looking at growth records of thousands of children across time, we saw early warning profiles that could signal children at risk."

This study highlights the importance of considering metabolic risk factors along with other influences like psychology, environment, and sociocultural components, Yilmaz said. "The differences in childhood body weight of adolescents who later developed eating disorders started to emerge at a very early age - way too early to be caused by social pressures to be thin or dieting. A more likely explanation is that underlying metabolic factors that are driven by genetics could predispose these individuals to weight dysregulation. This aligns with our other genetic work that has highlighted a metabolic component to anorexia nervosa."

“Clinically, this means that pediatricians should be alert for children who fall off and stay below the growth curve throughout childhood,” noted the co-author of the study, Cynthia Bulik, Ph.D., a Distinguished Professor of Eating Disorders at UNC. “This could be an early warning sign of risk for anorexia nervosa. The same holds for children who exceed and remain above the growth curve - only their risk is increased for the other eating disorders such as bulimia nervosa and binge-eating disorder."

"Our results also highlight the multi-factorial composition of eating disorders, as well as the need to develop early detection tools that could be used as part of routine checks by all pediatricians. Indeed, the earlier the problem is identified, the better it can be managed, especially if support is provided to the family as a whole, rather than just the individual," said the corresponding author of the study Nadia Micali, MD, MRCPsych Ph.D., a Professor with University of Geneva Faculty of Medicine and Head of Geneva University Hospitals' Division of Child and Adolescent Psychiatry.

In this video, Dr. Cynthia Bulik discusses eating disorders with the Karolinska Institute.

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